1. Field of the Invention
The present invention relates to a semiconductor device, and more particularly, to a semiconductor device having an insulating film whose relative dielectric constant is 3.8 or lower.
2. Description of the Related Art
As a structure of a semiconductor device (semiconductor chip) having an interlayer insulating film in which a side face of the interlayer insulating film, namely, the peripheral edge of the semiconductor chip is sealed for improving reliability, that disclosed in the following patent document 1 is an example. In this example, conductors made of the same material as that of wirings are used for seal members. In a manufacturing process thereof, the seal members are formed on the side faces of the interlayer insulating films, and thereafter, a semiconductor wafer is diced to semiconductor chips.
[Patent Document 1]
Japanese Patent Laid-open No. 2000-277465.
For the purpose of further improving the operating speed of a semiconductor device, decrease in wiring resistance, reduction in dielectric constant of an interlayer insulating film, and so on have been promoted in recent years. Specifically, copper (Cu) is replacing aluminum (Al) as the material of the wiring. As the interlayer insulating film, the adoption of a low dielectric constant insulating film (low-k film) such as a SiO2 film doped with fluorine or a SiO2 film containing an organic component is being promoted in place of the adoption of a simple SiO2 film.
The low dielectric constant insulating film is obtained by, for example, reduction in material density, exclusion of a dielectric polarization property in the material, or the like. The reduction in material density is achieved by, for example, making the material porous, but such a low dielectric constant insulating film is low in mechanical physical value such as Young's modulus and hardness. This means that the low dielectric constant insulating film is generally low in mechanical strength of its material itself.
Some low dielectric constant insulating film adopts a film structure low in polarity in order to lower a relative dielectric constant in the film. This structure decreases adhesion strength on interfaces of layered films in which low dielectric constant insulating films are layered or a low dielectric constant insulating film and a different film are layered.
The low mechanical strength of the low dielectric constant insulating film itself and the low adhesion strength on the interfaces of the layered films including the low dielectric constant insulating film may possibly be factors of causing problems in subsequent processes. As a result, reliability as a semiconductor device may possibly be impaired. Note that the aforesaid patent document 1 does not indicate any measure to be taken against the low mechanical strength of the interlayer insulating films and the low adhesion strength on the interfaces.